1. Field of the Invention
The present invention relates to a printing apparatus that prints an image by applying ink onto a print medium carried by a conveying belt.
2. Description of the Related Art
There is a printing apparatus that performs a printing operation by using an inkjet print head to print on a print medium as it is conveyed by a conveying belt that attracts the print medium thereto by static electricity. In such a printing apparatus, there is a possibility that ink adhering to the surface of the conveying belt may be transferred to the back of a next sheet of the print medium.
Japanese Patent Laid-Open No. 2004-137033 discloses a method of clearing the conveying belt of adhering ink by using a belt cleaning unit, such as a blade, which can be brought into or out of contact with the surface of the conveying belt. Japanese Patent Laid-Open No. 2007-069438 discloses a method of cleaning the conveying belt, which, during a double-side print mode that prints both sides of a print medium, brings a belt cleaning roller into contact with the conveying belt when the print medium, after having been printed on its front surface, is inverted to have its back surface printed.
These prior art technologies, however, have the following drawbacks. In the cleaning method of Japanese Patent Laid-Open No. 2004-137033, when, after the print medium is printed on its front surface during the double-side print mode, the conveying belt is reversed to pull the print medium to a print position, the following problem may arise. That is, ink staying in a nipping portion between the cleaning blade and the conveying belt may move along with the conveying belt and be transferred to a roller that is in contact with the conveying belt. In the cleaning method of Japanese Patent Laid-Open No. 2007-069438, since the belt cleaning roller is made of a material with a higher ink absorbing capability than that of the conveying belt, the ink that was absorbed by the cleaning roller may get transferred back again to the conveying belt. Further, in a marginless printing that leaves no blank margin at the rear edge of the print medium, the ink that was ejected beyond the rear edge of the print medium onto the conveying belt can only be cleared after the print medium being transported leaves the conveying belt.